NASA has announced it will roll the Artemis II rocket and capsule back into the Vehicle Assembly Building at Kennedy Space Center.
The space agency made the announcement on Monday 23 February, after engineers encountered an issue with the flow of helium to the rocket's upper stage.
Weather permitting, NASA could roll the Artemis II rocket assembly back into the Vehicle Assembly Building as early as Tuesday 24 February.
More on Artemis II
A setback for the mission to the Moon?
NASA's Artemis II mission is the first crewed flight of its Artemis programme.
The mission will see astronauts Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen travel further into space than any human being before them, on a 10-day journey around the Moon and back.
On 18 January 2026, NASA completed its rollout of the Space Launch System – the rocket – and the Orion capsule where the astronauts will be located during the flight.
The 4-mile journey from the Vehicle Assembly Building to the launch pad at Kennedy Space Center took about 12 hours.
The rollout complete, a first wet dress rehearsal concluded on 2 February 2026 and engineers reported issues with the supply of hydrogen fuel to the rocket.
They also encountered problems with the hatch of the Orion crew module.
A second wet dress rehearsal was completed on 19 February, with the hydrogen fuel and crew module problems seemingly resolved.
Following the conclusion of the second wet dress rehearsal, NASA announced it was ready to launch Artemis II in early March.
The astronauts then entered quarantine for the second time on 20 February, in preparation for launch.
However, over the weekend, NASA announced its engineers had discovered an interruption in the flow of helium to the Space Launch System.
Helium is required to keep the engine and fuel working as they should be.
NASA says potential causes could be related to the lines used to supply helium to the rocket, a faulty valve in the rocket's upper stage or a filter between the ground and the rocket.
The uncrewed Artemis I mission, which launched in November 2022, also encountered problems with the supply of helium, so NASA says its engineers are reviewing data from that mission to see if they can get any answers.
NASA has announced that, weather depending, the rocket and Orion module will be removed from the launch pad and rolled back into the Vehicle Assembly Building as early as 24 February.
"Returning to the Vehicle Assembly Building at Kennedy is required to determine the cause of the issue and fix it," NASA says.
"Teams are reviewing the exact time to begin the approximately 4 mile, multi-hour trek."
